Physical quantity sensor, electronic device, and mobile body

ABSTRACT

A physical quantity sensor has a first movable electrode section which has a portion facing a first fixed electrode section and a second movable electrode section which has a portion facing a second fixed electrode section, and is provided with a movable mass section which is formed in a shape which encloses a first fixed electrode side fixed section, a second fixed electrode side fixed section, a first movable electrode side fixed section, and a second movable electrode side fixed section in planar view.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a divisional of U.S. patent application Ser. No.15/187,953, filed Jun. 21, 2016, which claims priority to JapaneseApplication No. 2015-138779 filed Jul. 10, 2015, both of which arehereby incorporated by reference in their entireties.

BACKGROUND 1. Technical Field

The present invention relates to a physical quantity sensor, anelectronic device, and a mobile body.

2. Related Art

In recent years, a sensor has been developed that is manufactured usinga silicon micro electro mechanical systems (MEMS) technique. As such asensor, an electrostatic capacitive-type physical quantity sensor isknown which has a fixed electrode that is disposed to be fixed and amovable electrode which faces the fixed electrode with an intervaltherebetween and is provided to be displaceable, and detects a physicalquantity such as acceleration and angular velocity based onelectrostatic capacity between the two electrodes (for example, refer toJP-A-2010-071911 and JP-A-10-111312).

For example, the physical quantity sensor in JP-A-2010-071911 has twofixed electrode sections and a movable electrode section which areformed separated from one silicon wafer. In the physical quantitysensor, each fixed electrode section has a support conducting sectionwhich is fixed to a substrate front surface, an electrode supportsection with a fixed width dimension which extends linearly from thesupport conducting section, and a plurality of opposing electrodes whichare arranged to form a comb-tooth shape extending from the electrodesupport section. Meanwhile, the movable electrode section has twosupport conducting portions which are fixed to the substrate frontsurface, and support arm portions which extend from respective supportconducting portions, a weight section which is disposed in a regioninterposed by two support arm sections, an elastic support section whichsupports the weight section with respect to each support arm section,and a plurality of movable opposing electrodes which are disposedextending from the weight section so as to face the plurality ofopposing electrodes of the fixed electrode section described above.

In addition, for example, the physical quantity sensor according toJP-A-10-111312 has two mounting bars which are fixed to two anchorjoining regions on the front surface of the substrate, two deflectionsprings which are fixed to each of the both mounting bars, one centerbar which is joined to other end sections of four deflection springs, aplurality of movable electrodes which are mounted on the center bar, anda plurality of fixed electrodes which are respectively disposed facingthe plurality of movable electrodes being fixed to a plurality of anchorregions on the front surface of the substrate.

In such a physical quantity sensor in the related art, the movableelectrode and the fixed electrode are fixed and connected to a substratevia a plurality of connecting sections (support conducting section inJP-A-2010-071911 and anchor joining region in JP-A-10-111312), but aportion of the movable electrode (weight section in JP-A-2010-071911 andcenter bar in JP-A-10-111312) is positioned in planar view between twoconnecting sections out of the plurality of connecting sections. Forthis reason, in the physical quantity sensor in the related art, it isdifficult to shorten a distance between the two connecting sections andwhen the substrate is warped accompanying temperature variance, thewarping of the substrate is likely to influence the fixed electrode andthe movable electrode via the connecting section to be deformed, and asa result, there is a problem in that temperature characteristicsdeteriorate. Here, for example, the warping of the substrateaccompanying temperature variance occurs due to a linear expansioncoefficient difference between the substrate and a member which isjoined to the substrate (for example, a structure that includes themovable electrode and the fixed electrode, or a lid member forconfiguring a package which accommodates the substrate and thestructure).

SUMMARY

An advantage of some aspects of the invention is to provide a physicalquantity sensor with superior temperature characteristics, and providean electronic device and a mobile body that include the physicalquantity sensor.

The advantage is achieved by the aspects of the invention below.

According an aspect of the invention, there is provided a physicalquantity sensor including a first fixed electrode side fixed sectionwhich has a first fixed electrode section, a second fixed electrode sidefixed section which has a second fixed electrode section that isdisposed lined up with the first fixed electrode section along a firstdirection, a first movable electrode side fixed section and a secondmovable electrode side fixed section which are disposed lined up along asecond direction which intersects with the first direction, a movablemass section which has a first movable electrode section that has aportion facing the first fixed electrode section and a second movableelectrode section that has a portion facing the second fixed electrodesection and which is formed in a shape which encloses the first fixedelectrode side fixed section, the second fixed electrode side fixedsection, the first movable electrode side fixed section, and the secondmovable electrode side fixed section in planar view, a first elasticsection which connects the first movable electrode side fixed sectionand the movable mass section such that the movable mass section isdisplaceable in the second direction, and a second elastic section whichconnects the second movable electrode side fixed section and the movablemass section such that the movable mass section is displaceable in thesecond direction.

According to such a physical quantity sensor, it is possible torespectively shorten a distance between the two fixed electrode sidefixed sections (first fixed electrode side fixed section and secondfixed electrode side fixed section) and a distance between the twomovable electrode side fixed sections (first movable electrode sidefixed section and second movable electrode side fixed section) byforming the movable mass section as a frame body, and disposing the twofixed electrode side fixed sections and the two movable electrode sidefixed sections inside the movable mass section in planar view. For thisreason, even if the substrate on which the fixed electrode side fixedsection and the movable electrode side fixed section are fixed is warpedaccompanying temperature variance, the deformation of the fixedelectrode section and movable electrode section due to the warping ofthe substrate is reduced, and as a result, it is possible to achievesuperior temperature characteristics.

In the physical quantity sensor, it is preferable that the first movableelectrode section has a plurality of first movable electrode fingerswhich extend along the first direction, the second movable electrodesection has a plurality of second movable electrode fingers which extendalong the first direction, the first fixed electrode section has aplurality of first fixed electrode fingers which extend along the firstdirection, and the second fixed electrode section has a plurality ofsecond fixed electrode fingers which extend along the first direction.

Thereby, it is possible to increase electrostatic capacity changebetween the first fixed electrode section and the first movableelectrode section and between the second fixed electrode section and thesecond movable electrode section accompanying displacement of themovable mass section. For this reason, it is possible to achieve thephysical quantity sensor with high sensitivity.

In the physical quantity sensor, it is preferable that the first fixedelectrode side fixed section has a first extending section which extendsalong the second direction and supports the plurality of first fixedelectrode fingers, and the second fixed electrode side fixed section hasa second extending section which extends along the second direction andsupports the plurality of second fixed electrode fingers.

Thereby, it is possible to effectively increase the number of fixedelectrode fingers and movable electrode fingers. For this reason, it ispossible to further increase electrostatic capacity change between thefirst fixed electrode section and the first movable electrode sectionand between the second fixed electrode section and the second movableelectrode section accompanying displacement of the movable mass section.

In the physical quantity sensor, it is preferable that the firstextending section is disposed on one side in the first direction withrespect to the first movable electrode side fixed section and the secondmovable electrode side fixed section, and the second extending sectionis disposed on the other side in the first direction with respect to thefirst movable electrode side fixed section and the second movableelectrode side fixed section.

Thereby, it is possible to reduce noise by carrying out a differentialcalculation of a signal according to electrostatic capacity changebetween the first fixed electrode section and the first movableelectrode section and a signal according to electrostatic capacitychange between the second fixed electrode section and the second movableelectrode section.

The physical quantity sensor, preferably further includes a substrate, afirst fixed electrode side wiring provided on the substrate andelectrically connected to the first fixed electrode fingers, and asecond fixed electrode side wiring provided on the substrate andelectrically connected to the second fixed electrode fingers, in whichthe first extending section preferably has a portion which is separatedfrom the substrate and in planar view overlapping with the first fixedelectrode side wiring, and the second extending section preferably has aportion which is separated from the substrate and in planar viewoverlapping with the second fixed electrode side wiring.

Thereby, since the extending section and the fixed electrode side wiringhave the same potential as each other, it is possible to reduceparasitic capacitance which occurs between the substrate and eachextending section with the extending section and the fixed electrodeside wiring overlapping with each other in planar view. As a result, itis possible to achieve superior detection characteristics of thephysical quantity sensor.

The physical quantity sensor preferably further includes a substrate anda movable electrode side wiring provided on the substrate andelectrically connected respectively to the first movable electrodefingers and the second movable electrode fingers, in which respectivetip end sections of the first movable electrode fingers and the secondmovable electrode fingers preferably overlap with the movable electrodeside wiring in planar view.

Thereby, when the structure which includes the movable electrode sidefixed section and the substrate are anodically bonded, since the tip endsection of the movable electrode finger faces the movable electrode sidewiring with the same potential as the tip end section, an electric fieldis reduced which is generated between the tip end section of the movableelectrode finger and the substrate, and as a result, it is possible toprevent or reduce sticking of each movable electrode finger on thesubstrate.

The physical quantity sensor preferably further includes a substrate,and a movable electrode side wiring which is provided on the substrate,in which at least one fixed section of the first movable electrode sidefixed section and the second movable electrode side fixed sectionpreferably has a plurality of connecting sections which are connected tothe substrate.

Thereby, it is possible to more stably connect the substrate and themovable electrode side fixed section. In addition, it is possible todispose a contact section between two adjacent connecting sections. Forthis reason, since it is possible to dispose the contact section in thecenter, it is possible to more stably electrically connect the contactsection and the movable electrode side fixed section.

In addition, it is possible to perform electrical contact between thestructure which includes the first movable electrode side fixed sectionand the second movable electrode side fixed section which have the samepotential as each other and the movable electrode side wiring at aplurality of locations. For this reason, it is possible to increasecontact reliability.

The physical quantity sensor preferably further includes a conductivecontact section which is provided in contact with both of the connectingsection and the movable electrode side wiring being positionedtherebetween.

Thereby, it is possible to increase reliability of electrical contactbetween the structure which includes the first movable electrode sidefixed section and the second movable electrode side fixed section whichhave the same potential as each other and the movable electrode sidewiring.

The physical quantity sensor preferably further includes a projectingsection which is provided on a main surface of the substrate overlappingwith the movable mass section in planar view.

Thereby, it is possible to regulate movement in an out-of-plane surfacedirection of the movable mass section using the projecting section, andas a result, it is possible to prevent or reduce sticking of the movablemass section on the substrate.

In the physical quantity sensor, it is preferable that each of the firstfixed electrode side fixed section and the second fixed electrode sidefixed section has a portion which is positioned between the firstmovable electrode side fixed section and the second movable electrodeside fixed section in planar view.

Thereby, it is possible to shorten a distance between the two fixedelectrode side fixed sections, and as a result, it is possible toachieve further superior temperature characteristics.

The physical quantity sensor preferably further includes a linkingsection which links the first movable electrode side fixed section andthe second movable electrode side fixed section, and is configured bythe same material as the first movable electrode side fixed section andthe second movable electrode side fixed section.

Thereby, it is possible to electrically connect the two movableelectrode side fixed sections via the linking section. For this reason,it is possible to reduce the occurrence of a potential differencebetween the first movable electrode side fixed section and the secondmovable electrode side fixed section, and realize stable sensorcharacteristics. In addition, since the linking section fixes the firstmovable electrode side fixed section and the second movable electrodeside fixed section being configured by the same material, it is possibleto collectively form the two movable electrode side fixed sections andthe linking section from the same substrate.

In the physical quantity sensor, it is preferable that the first movableelectrode side fixed section has a first support section which extendsalong the second direction, the second movable electrode side fixedsection has a second support section which extends along the seconddirection, the first elastic section extends from the first supportsection, and the second elastic section extends from the second supportsection.

Thereby, it is possible to increase the distance between the firstelastic section and the second elastic section. For this reason, it ispossible to reduce the displacement in an out-of-plane surface directionof the movable mass section. For this reason, it is possible to improveimpact resistance of the physical quantity sensor.

According to another aspect of the invention, there is provided anelectronic device including the physical quantity sensor.

According to such an electronic device, since the physical quantitysensor has superior temperature characteristics, it is possible toincrease reliability.

According to still another aspect of the invention, there is provided amobile body including the physical quantity sensor.

According to such a mobile body, since the physical quantity sensor hassuperior temperature characteristics, it is possible to increasereliability.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will be described with reference to the accompanyingdrawings, wherein like numbers reference like elements.

FIG. 1 is a planar view illustrating a physical quantity sensoraccording to a first embodiment of the invention.

FIG. 2 is a sectional view taken along line II-II in FIG. 1.

FIG. 3 is a sectional view taken along line III-III in FIG. 1.

FIG. 4 is a partial expanded planar view for describing a first fixedelectrode section and a first movable electrode section which areprovided in the physical quantity sensor illustrated in FIG. 1.

FIG. 5 is a partial expanded planar view for describing a first elasticsection which are provided in the physical quantity sensor illustratedin FIG. 1.

FIG. 6 is a planar view for describing a support substrate and a wiringpattern which are provided in the physical quantity sensor illustratedin FIG. 1.

FIG. 7 is a planar view illustrating a physical quantity sensoraccording to a second embodiment of the invention.

FIG. 8 is a perspective view schematically illustrating a configurationof a mobile type personal computer which is an example of an electronicdevice in the invention.

FIG. 9 is a perspective view schematically illustrating a configurationof a mobile phone which is an example of the electronic device in theinvention.

FIG. 10 is a perspective view illustrating a configuration of a digitalstill camera which is an example of the electronic device of theinvention.

FIG. 11 is a perspective view illustrating a configuration of anautomobile which is an example of a mobile body of the invention.

DESCRIPTION OF EXEMPLARY EMBODIMENTS

A physical quantity sensor, an electronic device, and a mobile body ofthe invention will be described below in detail based on the embodimentswhich are illustrated in the drawings.

1. Physical Quantity Sensor

First, a physical quantity sensor of the invention will be described.

First Embodiment

FIG. 1 is a planar view illustrating a physical quantity sensoraccording to a first embodiment of the invention, FIG. 2 is a sectionalview taken along line II-II in FIG. 1, and FIG. 3 is a sectional viewalong line III-III in FIG. 1. FIG. 4 is a partial expanded planar viewfor describing a first fixed electrode section and a first movableelectrode section which is provided with the physical quantity sensorillustrated in FIG. 1. FIG. 5 is a partial expanded planar view fordescribing a first elastic section which is provided with the physicalquantity sensor illustrated in FIG. 1. FIG. 6 is a planar view fordescribing a support substrate and a wiring pattern which are providedwith the physical quantity sensor illustrated in FIG. 1.

Here, in each diagram, for convenience of explanation, an X axis (firstaxis), a Y axis (second axis), and a Z axis (third axis) which are threeaxes which are orthogonal to each other are illustrated as arrows, tipend sides of the arrows are set as “+ (plus)” and the base end side isset as “− (minus)”. In addition, hereinafter a direction (firstdirection) which is parallel to the X axis is referred to as an “X axisdirection”, a direction (second direction) which is parallel to the Yaxis is referred to as a “Y axis direction”, and a direction which isparallel to the Z axis is referred to as a “Z axis direction”. Inaddition, for convenience of explanation, hereinafter an upper side (+Zaxis direction side) in FIG. 2 and FIG. 3 is set as “upper”, and a lowerside (−Z axis direction side) is set as “lower”.

As shown in FIGS. 1 to 3, the physical quantity sensor 1 of theembodiment has a sensor element 10, a substrate 4 which supports thesensor element 10, a wiring pattern 5 which is electrically connected tothe sensor element 10 on the substrate 4, and a lid member 6 which isjoined to the substrate 4 so as to cover the sensor element 10. Here,the substrate 4 and the lid member 6 configure a package 20 that forms aspace S that stores the sensor element 10. Each section which configuresthe physical quantity sensor 1 will be described below in order.

Sensor Element 10

As shown in FIG. 1, the sensor element 10 has a first fixed electrodeside fixed section 21 a, a second fixed electrode side fixed section 21b, a first movable electrode side fixed section 31 a, and a secondmovable electrode side fixed section 31 b which are fixed to thesubstrate 4, a movable mass section 32 which encloses the fixed sectionsin planar view, and two first elastic sections 33 a and two secondelastic sections 33 b which are connected to the first movable electrodeside fixed section 31 a, the second movable electrode side fixed section31 b, and the movable mass section 32.

Here, the first movable electrode side fixed section 31 a, the secondmovable electrode side fixed section 31 b, the movable mass section 32,the two first elastic sections 33 a, and two second elastic sections 33b are formed integrally to configure a movable electrode side structure3. That is, the sensor element 10 has the first fixed electrode sidefixed section 21 a, the second fixed electrode side fixed section 21 b,and the movable electrode side structure 3 which are disposed atintervals with a gap from each other, and the movable electrode sidestructure 3 has the first movable electrode side fixed section 31 a, thesecond movable electrode side fixed section 31 b, the movable masssection 32, the first elastic section 33 a, and the second elasticsection 33 b which are integrally formed. Here, in the embodiment, thesensor element 10 has a form with rotational symmetry in planar view.

The first fixed electrode side fixed section 21 a and the second fixedelectrode side fixed section 21 b are disposed lined up along the X axisdirection. Here, the first fixed electrode side fixed section 21 a isdisposed on the +X axis direction side with respect to the center of thesensor element 10, and meanwhile, the second fixed electrode side fixedsection 21 b is disposed on the −X axis direction side with respect tothe center of the sensor element 10.

The first fixed electrode side fixed section 21 a has a connectingsection 211 a which is connected to the substrate 4, a first extendingsection 212 a which extends from the connecting section 211 a alongrespective directions of a +Y axis direction and a −Y axis direction andseparated from the substrate 4, and a first fixed electrode section 213a which is connected to the first extending section 212 a. The firstfixed electrode section 213 a is configured by a plurality of firstfixed electrode fingers 2131 a which are supported by an end in thefirst extending section 212 a (refer to FIG. 4). The plurality of firstfixed electrode fingers 2131 a extend along the +X axis direction fromthe first extending section 212 a and are disposed lined up at intervalswith a gap along the Y axis direction, and configure the “first fixedelectrode comb section” which has a comb-tooth shape.

In the same manner, the second fixed electrode side fixed section 21 bhas a connecting section 211 b which is connected to the substrate 4, asecond extending section 212 b which extends from the connecting section211 b along respective directions of the +Y axis direction and the −Yaxis direction and separated from the substrate 4, and a second fixedelectrode section 213 b which is connected to the second extendingsection 212 b. The second fixed electrode section 213 b is disposedlined up along the X axis direction with respect to the first fixedelectrode section 213 a described above, and is configured by aplurality of second fixed electrode fingers 2131 b which are supportedby an end on the second extending section 212 b. The plurality of secondfixed electrode fingers 2131 b extend along the −X axis direction fromthe second extending section 212 b and are disposed lined up atintervals with a gap along the Y axis direction, and configure the“second fixed electrode comb section” which has a comb-tooth shape.

Meanwhile, the first movable electrode side fixed section 31 a and thesecond movable electrode side fixed section 31 b are disposed lined upalong the Y axis direction which intersects with the X axis direction.Here, the first movable electrode side fixed section 31 a is disposed onthe +Y axis direction side with respect to the center of the sensorelement 10, and meanwhile, the second movable electrode side fixedsection 31 b is disposed on the −Y axis direction side with respect tothe center of the sensor element 10. In the embodiment, in planar view,the first movable electrode side fixed section 31 a is disposed on the+Y axis direction side and the second movable electrode side fixedsection 31 b is disposed on the −Y axis direction side with respect tothe connecting sections 211 a and 211 b. Accordingly, the first fixedelectrode side fixed section 21 a and the second fixed electrode sidefixed section 21 b respectively have a portion (connecting sections 311a and 311 b) which is positioned between the first movable electrodeside fixed section 31 a and the second movable electrode side fixedsection 31 b in planar view.

The first movable electrode side fixed section 31 a has the connectingsection 311 a which is connected to the substrate 4 and a first supportsection 312 a which extends from the connecting section 311 a along the+Y axis direction. The end section (end section 3121 a which isillustrated in FIG. 5) on the +Y axis direction side of the firstsupport section 312 a has a narrow width.

In the same manner, the second movable electrode side fixed section 31 bhas the connecting section 311 b which is connected to the substrate 4and a second support section 312 b which extends from the connectingsection 311 b along the −Y axis direction. The end section on the −Yaxis direction side of the second support section 312 b has a narrowwidth.

In this manner, the first fixed electrode side fixed section 21 a, thesecond fixed electrode side fixed section 21 b, the first movableelectrode side fixed section 31 a, and the second movable electrode sidefixed section 31 b are disposed inside the movable mass section 32 whichhas a frame shape in planar view. In other words, in planar view, themovable mass section 32 has a shape which is enclosed by the first fixedelectrode side fixed section 21 a, the second fixed electrode side fixedsection 21 b, the first movable electrode side fixed section 31 a, andthe second movable electrode side fixed section 31 b.

The movable mass section 32 has a frame section 321 which is a frameshape in planar view, a first movable electrode section 322 a and asecond movable electrode section 322 b which are connected to the framesection 321.

Here, the first movable electrode section 322 a has a portion whichfaces the first fixed electrode section 213 a described above. Indetail, the first movable electrode section 322 a is configured by aplurality of first movable electrode fingers 3221 a which are disposedextending inside the frame section 321 so as to mesh with a gap g atintervals with respect to the plurality of first fixed electrode fingers2131 a (first fixed electrode comb section) of the first fixed electrodesection 213 a described above and in which an end is supported on theframe section 321 (refer to FIG. 4). The plurality of first movableelectrode fingers 3221 a extend along the −X axis direction from theframe section 321 and are disposed lined up at intervals with a gapalong the Y axis direction, and configure the “first movable electrodecomb section” which has a comb-tooth shape.

In the same manner, the second movable electrode section 322 b has aportion which faces the second fixed electrode section 213 b describedabove. In detail, the second movable electrode section 322 b isconfigured by a plurality of second movable electrode fingers 3221 bwhich are disposed extending inside the frame section 321 so as to meshwith a gap at intervals with respect to the plurality of second fixedelectrode fingers 2131 b of the second fixed electrode section 213 bdescribed above and in which an end is supported on the frame section321. The plurality of second movable electrode fingers 3221 b extendalong the +X axis direction from the frame section 321 and are disposedlined up at intervals with a gap along the Y axis direction, andconfigure the “second fixed electrode comb section” which has acomb-tooth shape.

Such a movable mass section 32 is supported via two first elasticsections 33 a with respect to the first movable electrode side fixedsection 31 a described above, and is supported via two second elasticsections 33 b with respect to the second movable electrode side fixedsection 31 b described above. Accordingly, in planar view, not only thefirst fixed electrode side fixed section 21 a, the second fixedelectrode side fixed section 21 b, the first movable electrode sidefixed section 31 a, and the second movable electrode side fixed section31 b described above, but the two first elastic sections 33 a and thetwo second elastic sections 33 b are disposed inside the movable masssection 32 which is a frame shape.

Two first elastic sections 33 a are respectively connected to the firstmovable electrode side fixed section 31 a and the movable mass section32 in which the movable mass section 32 is displaceable in the Y axisdirection. In the same manner, two second elastic sections 33 b arerespectively connected to the second movable electrode side fixedsection 31 b and the movable mass section 32 in which the movable masssection 32 is displaceable in the Y axis direction.

In more detail, two first elastic sections 33 a have a shape so as torespectively extend in the +Y axis direction while meandering such thatapproach and separation are repeated with each other in the X axisdirection from the end section of the +Y axis direction side of thefirst extending section 212 a of the first fixed electrode side fixedsection 21 a described above. That is, as shown in FIG. 5, each firstelastic section 33 a has a portion 331 a (beam) which extends along theX axis direction from the end section 3121 a of the +Y axis directionside of the first support section 312 a, a portion 332 a (beam) whichextends along the X axis direction from the portion 3211 which protrudesinside the frame section 321, and a portion 333 a (linking section)which links each end section of the portions 331 a and 332 a.

In the same manner, two second elastic sections 33 b have a shape so asto respectively extend in the −Y axis direction while meandering suchthat approach and separation are repeated with each other in the X axisdirection from the end section of the −Y axis direction side of thesecond support section 312 b of the second fixed electrode side fixedsection 21 b described above.

Here, if the shape of the first elastic section 33 a and the secondelastic section 33 b is able to displace the movable mass section 32 inthe Y axis direction, the shape is not limited to the description above,for example, may be configured by one beam which extends along the Xaxis direction, and may be configured by three or more beams and two ormore linking sections which link with the beams.

The configuration material of the first fixed electrode side fixedsection 21 a, the second fixed electrode side fixed section 21 b, andthe movable electrode side structure 3 as described above arerespectively not particularly limited, but for example, it is preferablethat a silicon material (such as single crystal silicon or polysilicon)to which conductivity is imparted by impurities such as phosphorus andboron being doped.

In addition, the first fixed electrode side fixed section 21 a, thesecond fixed electrode side fixed section 21 b, and the movableelectrode side structure 3 are able to collectively form one substrate(for example, silicon substrate) by etching. In this case, it ispossible to simply and with high precision align the thickness of eachsection of the sensor element 10. In addition, it is possible to processsilicon with high precision by etching.

In the sensor element 10 which is configured as described above, whenacceleration in the Y axis direction which is a detection axis directionis received by the sensor element 10, the movable mass section 32 isdisplaced in the Y axis direction accompanying elastic deformation ofthe first elastic section 33 a and the second elastic section 33 b. Bydoing this, a distance between the first fixed electrode fingers 2131 aof the first fixed electrode section 213 a and the first movableelectrode fingers 3221 a of the first movable electrode section 322 a,and a distance between the second fixed electrode fingers 2131 b of thesecond fixed electrode section 213 b and the second movable electrodefingers 3221 b of the second movable electrode section 322 b arerespectively changed.

Accordingly, it is possible to detect the size of acceleration which isreceived by the sensor element 10 based on electrostatic capacitybetween the distances. In the embodiment, out of a distance between thefirst fixed electrode fingers 2131 a and the first movable electrodefingers 3221 a and a distance between the second fixed electrode fingers2131 b and the second movable electrode fingers 3221 b, one distance islarge, and the other distance is small. For this reason, out ofelectrostatic capacity between the first fixed electrode fingers 2131 aand the first movable electrode fingers 3221 a and electrostaticcapacity between the second fixed electrode fingers 2131 b and thesecond movable electrode fingers 3221 b, one electrostatic capacity islarge, and the other electrostatic capacity is small. Therefore,differential calculation is carried out on a signal based onelectrostatic capacity between the first fixed electrode fingers 2131 aof the first fixed electrode section 213 a and the first movableelectrode fingers 3221 a of the first movable electrode section 322 a,and a signal based on electrostatic capacity between the second fixedelectrode fingers 2131 b of the second fixed electrode section 213 b andthe second movable electrode fingers 3221 b of the second movableelectrode section 322 b. Thereby, it is possible to reduce noise byremoving a signal component accompanying displacement of the movablemass section 32 outside the detection signal axis direction, and outputa signal according to acceleration which is received by the sensorelement 10.

Substrate

The substrate 4 (support substrate) has a plate form, and is disposedalong the XY horizontal plane (reference surface) which is a horizontalplane that includes the X axis and the Y axis. As shown in FIGS. 2 and3, a concave section 41 is provided on an upper surface (surface of aside on which the sensor element 10 is provided) of the substrate 4. Theconcave section 41 has a function which prevents a movable portion(portion which excludes the connecting sections 211 a, 211 b, 311 a, and311 b described above) of the sensor element 10 coming into contact withthe substrate 4. Thereby, driving of the sensor element 10 ispermissible, and it is possible for the substrate 4 to support thesensor element 10.

In addition, a first projecting section 42 a, a second projectingsection 42 b, four projecting sections 43, and four projecting sections44 are provided which protrude from the bottom surface of the concavesection 41 on the upper surface of the substrate 4.

The first projecting section 42 a and the second projecting section 42 bhave a function which supports the sensor element 10 in a state in whichthe movable portion of the sensor element 10 is suspended with respectto the substrate 4.

As shown in FIG. 6, when described in detail, the first projectingsection 42 a and the second projecting section 42 b are disposed linedup along the X axis direction. Here, the first projecting section 42 ais disposed on the +X axis direction side with respect to the center ofthe sensor element 10, and meanwhile, the second projecting section 42 bis disposed on the −X axis direction side with respect to the center ofthe sensor element 10. Then, the first projecting section 42 a and thesecond projecting section 42 b respectively extend along the Y axisdirection.

In this manner, the connecting section 211 a of the first fixedelectrode side fixed section 21 a described above is joined to thecenter in the Y axis direction of the first projecting section 42 a.Meanwhile, the connecting section 211 b of the second fixed electrodeside fixed section 21 b described above is joined to the center in the Yaxis direction of the second projecting section 42 b.

In addition, the connecting section 311 a of the first movable electrodeside fixed section 31 a described above is joined to the end section inthe +Y axis direction of the first projecting section 42 a and thesecond projecting section 42 b. Meanwhile, the connecting section 311 bof the second movable electrode side fixed section 31 b described aboveis joined to the end section in the −Y axis direction of the firstprojecting section 42 a and the second projecting section 42 b.

Four projecting sections 43 and four projecting sections 44 have afunction of preventing sticking of a suspended portion (in particular,the movable mass section 32) of the sensor element 10 on the substrate4.

When described in detail, in planar view, the four projecting sections43 are disposed at positions which overlap with an outer peripheralsection of the movable mass section 32 described above (in furtherdetail, in planar view, four corner sections of the frame section 321which has an outer shape of a square shape). Thereby, it is possible toeffectively reduce sticking of the movable mass section 32 on thesubstrate 4.

In addition, in planar view, the four projecting sections 44 aredisposed at positions which overlap with the movable mass section 32 inthe vicinity of a portion (portion in which there is a large electricfield during anode adjustment) in which the upper surface of thesubstrate 4 is exposed from the wiring pattern 5 which will be describedlater. Thereby, it is possible to effectively reduce sticking of themovable mass section 32 on the substrate 4.

In addition, the configuration material of the substrate 4 is notparticularly limited, but it is preferable to use a substrate materialwhich has insulation properties, in detail, it is preferable to use aquartz substrate, a sapphire substrate, and a glass substrate, and inparticular, it is preferable to use a glass material (for example,borosilicate glass such as Pyrex glass (registered trademark)) whichincludes alkali metal ions (movable ions). Thereby, in a case where thesensor element 10 or the lid member 6 is configured of silicon as themain material, it is possible to anodically bond the sensor element 10and the lid member 6 to the substrate 4.

Here, in the illustrations, the substrate 4 is configured by one member,but may be configured by bonding two or more members. For example, thesubstrate 4 may be configured by bonding together a member with a frameform and a member with a plate form.

In addition, for example, it is possible to form the substrate 4 using aphotolithography method, an etching method, or the like.

Wiring Pattern

As shown in FIG. 6, the wiring pattern 5 is provided on an upper surfaceof the substrate 4 described above. The wiring pattern 5 has a firstfixed electrode side wiring 51 a which is electrically connected to thefirst fixed electrode side fixed section 21 a described above, a secondfixed electrode side wiring 51 b which is electrically connected to thesecond fixed electrode side fixed section 21 b, and movable electrodeside wirings 52 a, 52 b, and 53 which are electrically connected to thefirst movable electrode side fixed section 31 a and the second movableelectrode side fixed section 31 b.

The first fixed electrode side wiring 51 a is disposed extending to the−Y axis direction side from the vicinity of the first projecting section42 a described above. A terminal section on the +Y axis direction sideof the first fixed electrode side wiring 51 a is connected to the firstfixed electrode side fixed section 21 a via the first contact section 54a. In addition, the terminal section on the +Y axis direction side ofthe first fixed electrode side wiring 51 a is extracted externally tothe package 20 and is electrically connected to an external terminalwhich is not shown in the drawings. In the same manner, the second fixedelectrode side wiring 51 b is disposed extending to a +Y axis directionside from the vicinity of the second projecting section 42 b describedabove. A terminal section on the −Y axis direction side of the secondfixed electrode side wiring 51 b is connected to the second fixedelectrode side fixed section 21 b via the second contact section 54 b.In addition, the terminal section on the +Y axis direction side of thesecond fixed electrode side wiring 51 b is extracted externally to thepackage 20 and is electrically connected to the external terminal whichis not shown in the drawings. Here, a portion which connects to thefirst contact section 54 a of the first fixed electrode side fixedsection 21 a is able to be said to configure a section of the connectingsection 211 a which is connected to the substrate 4 of the first fixedelectrode side fixed section 21 a described above. In the same manner, aportion which connects to the second contact section 54 b of the secondfixed electrode side fixed section 21 b is able to be said to configurea section of the connecting section 211 b which is connected to thesubstrate 4 of the second fixed electrode side fixed section 21 bdescribed above.

In particular, the movable electrode side wiring 52 a is disposed on the+X axis direction side with respect to the first projecting section 42 aso as to overlap as much as possible with a portion (in particular, themovable mass section 32) on the +X axis direction side of the sensorelement 10. In the same manner, in planar view, the movable electrodeside wiring 52 b is disposed on the −X axis direction side with respectto the second projecting section 42 b so as to overlap as much aspossible with a portion (in particular, the movable mass section 32) onthe −X axis direction side of the sensor element 10.

The movable electrode side wiring 53 has a portion which is disposedbetween the first projecting section 42 a and the second projectingsection 42 b, and is connected to the movable electrode side wiring 52 aand the movable electrode side wiring 52 b. Then, the movable electrodeside wiring 53 is connected to the first movable electrode side fixedsection 31 a via a third contact section 55 a, and is connected to thesecond movable electrode side fixed section 31 b via a fourth contactsection 55 b. Here, a portion which connects to the third contactsection 55 a of the first movable electrode side fixed section 31 a isable to be said to configure a section of the connecting section 311 awhich is connected to the substrate 4 of the first movable electrodeside fixed section 31 a described above. In the same manner, a portionwhich connects to the fourth contact section 55 b of the second movableelectrode side fixed section 31 b is able to be said to configure asection of the connecting section 311 b which is connected to thesubstrate 4 of the second movable electrode side fixed section 31 bdescribed above.

The configuration material of such a wiring pattern 5 is notparticularly limited as long as the configuration material hasconductivity, respectively various electrode materials are used, and itis possible to use a transparent electrode material such as indium tinoxide (ITO), zinc oxide (ZnO), a metal material such as gold (Au), goldalloy, platinum (Pt), aluminum (Al), aluminum alloy, silver (Ag), silveralloy, chromium (Cr), chromium alloy, copper (Cu), molybdenum (Mo),niobium (Nb), tungsten (W), iron (Fe), titanium (Ti), cobalt (Co), zinc(Zn), zirconium (Zr), and a semiconductor material such as silicon (Si).

In addition, the wiring pattern 5 collectively forms a film on which amaterial such as described above is formed using a sputtering method anda vapor deposition method such as an evaporation method by patterningusing the photolithography method, the etching method, and the like.Here, in a case where the substrate 4 is configured by a semiconductormaterial such as silicon, it is preferable to provide an insulationlayer between the substrate 4 and the wiring pattern 5. For example, itis possible to use silicon oxide (SiO₂), aluminum nitride (AlN), siliconnitride (SiN), and the like as the configuration material of theinsulation layer.

In addition, the respective configuration materials of each contactsection are not particularly limited as long as the configurationmaterials have conductivity, it is possible to use various electrodematerials in the same manner as the wiring pattern 5, but for example,it is preferable to use an elemental metal such as Au, Pt, Ag, Cu, andAl, or a metal of an alloy or the like which include the elementalmetals. It is possible to reduce contact resistance between the wiringpattern 5 and the sensor element 10 by configuring each contact sectionusing such metal.

Lid Member

The lid member 6 has a function which protects the sensor element 10described above.

The lid member 6 is joined to the substrate 4 described above, and thespace S is formed in which the sensor element 10 is housed within thesubstrate 4.

When described in detail, the lid member 6 has a plate form, and isprovided with a concave section 61 on the upper surface (surface on thesensor element 10 side). The concave section 61 is formed so as topermit displacement of a movable portion of the sensor element 10.

Then, a portion further outside than the concave section 61 on the lowersurface of the lid member 6 is joined to the upper surface of thesubstrate 4 described above. The joining method of the lid member 6 andthe substrate 4 is not particularly limited, but, for example, it ispossible to use a joining method which uses an adhesive, an anodicbonding method, a direct joining method, and the like.

In addition, as long as it is possible to exhibit the function asdescribed above, the configuration material of the lid member 6 is notparticularly limited, but, for example, it is possible to appropriatelyuse a silicon material, a glass material, or the like.

According to the physical quantity sensor 1 as described above, inplanar view, it is possible to respectively shorten a distance betweenthe first fixed electrode side fixed section 21 a and the second fixedelectrode side fixed section 21 b and a distance between the firstmovable electrode side fixed section 31 a and the second movableelectrode side fixed section 31 b by framing the movable mass section32, and disposing the two fixed electrode side fixed sections (the firstfixed electrode side fixed section 21 a and the second fixed electrodeside fixed section 21 b) and the two movable electrode side fixedsections (the first movable electrode side fixed section 31 a and thesecond movable electrode side fixed section 31 b) inside the movablemass section 32. For this reason, even if the substrate 4 is warpedaccompanying temperature variance, the influence of warping of thesubstrate 4 is received by the sensor element 10 is reduced, and as aresult, it is possible to set superior temperature characteristics.Moreover, it is possible to make one distance (a distance between thefirst fixed electrode side fixed section 21 a and the second fixedelectrode side fixed section 21 b in the embodiment) which is selected(for example, selected distance at which the influence of temperaturecharacteristics is easily received) according to necessarycharacteristics extremely short out of the two distances described aboveby disposing the first fixed electrode side fixed section 21 a and thesecond fixed electrode side fixed section 21 b lined up along the X axisdirection, and disposing the first movable electrode side fixed section31 a and the second movable electrode side fixed section 31 b lined upalong the Y axis direction which intersects with the X axis direction.

Here, for example, warping of the substrate 4 due to temperaturevariations occurs due to a linear expansion coefficient differencebetween the substrate 4 and the sensor element 10 or the lid member 6.For this reason, in a case where there is such a linear expansioncoefficient difference, it is possible to cause an effect in which thetemperature characteristics as described above are improved toremarkably occur.

In addition, in the physical quantity sensor 1, since each first movableelectrode finger 3221 a, each second movable electrode finger 3221 b,each first fixed electrode finger 2131 a, and each second fixedelectrode finger 2131 b extend along the X axis direction which isorthogonal to the detection axis direction, it is possible to increaseelectrostatic capacity change respectively between the first fixedelectrode section 213 a and the first movable electrode section 322 aand between the second fixed electrode section 213 b and the secondmovable electrode section 322 b accompanying displacement of the movablemass section 32. For this reason, it is possible to design the physicalquantity sensor 1 with high sensitivity.

In addition, since the first extending section 212 a and the secondextending section 212 b respectively extend along the Y axis directionwhich is the detection axis direction, it is possible to effectivelyincrease the number of each of the first movable electrode fingers 3221a, the second movable electrode fingers 3221 b, the first fixedelectrode fingers 2131 a, and the second fixed electrode fingers 2131 b.For this reason, it is possible to further increase electrostaticcapacity change respectively between the first fixed electrode section213 a and the first movable electrode section 322 a and between thesecond fixed electrode section 213 b and the second movable electrodesection 322 b accompanying displacement of the movable mass section 32.

In addition, as described above, the first extending section 212 a isdisposed on one side in the X axis direction with respect to the firstmovable electrode side fixed section 31 a and the second movableelectrode side fixed section 31 b, and the second extending section 212b is disposed on another side in the X axis direction with respect tothe first movable electrode side fixed section 31 a and the secondmovable electrode side fixed section 31 b. Thereby, as described above,it is possible to reduce noise by carrying out a differentialcalculation of a signal according to electrostatic capacity changebetween the first fixed electrode section 213 a and the first movableelectrode section 322 a and a signal according to electrostatic capacitychange between the second fixed electrode section 213 b and the secondmovable electrode section 322 b.

In addition, in planar view, the first extending section 212 a has aportion which overlaps with the first fixed electrode side wiring 51 awhich is electrically connected to the first fixed electrode fingers2131 a. In the same manner, in planar view, the second extending section212 b has a portion which overlaps with the second fixed electrode sidewiring 51 b which is electrically connected to the second fixedelectrode fingers 2131 b. Here, the first extending section 212 a andthe first fixed electrode side wiring 51 a have the same potential aseach other, and in addition, the second extending section 212 b and thesecond fixed electrode side wiring 51 b have the same potential as eachother. For this reason, it is possible to reduce parasitic capacitancewhich occurs between the substrate 4 and the first extending section 212a and the second extending section 212 b due to the first extendingsection 212 a and the first fixed electrode side wiring 51 a overlappingin planar view and the second extending section 212 b and the secondfixed electrode side wiring 51 b overlapping in planar view. As aresult, it is possible to set a superior detection characteristic of thephysical quantity sensor 1.

In addition, in planar view, a tip end section of the first movableelectrode fingers 3221 a overlaps with the movable electrode side wiring52 a which is electrically connected to the first movable electrodefingers 3221 a, and a tip end section of the second movable electrodefingers 3221 b overlaps with the movable electrode side wiring 52 bwhich is electrically connected to the second movable electrode fingers3221 b. Thereby, for example, when the sensor element 10 which is astructure that includes the first fixed electrode side fixed section 21a and the second fixed electrode side fixed section 21 b and thesubstrate 4 are anodically bonded, the tip end section of the firstmovable electrode fingers 3221 a face the movable electrode side wiring52 a with the same potential, and the tip end section of the secondmovable electrode fingers 3221 b face the movable electrode side wiring52 b with the same potential. For this reason, during anodical bonding,a field is reduced which is generated between the tip end section of thefirst movable electrode fingers 3221 a and the second movable electrodefingers 3221 b and the substrate 4, and as a result, it is possible toprevent or reduce sticking of each first movable electrode finger 3221 aand each second movable electrode finger 3221 b on the substrate 4.

In addition, as described above, both of the connecting section 311 a ofthe first movable electrode side fixed section 31 a and the connectingsection 311 b of the second movable electrode side fixed section 31 bare connected to the movable electrode side wiring 53. Thereby, it ispossible to perform electrical contact between the movable electrodeside structure 3 which is a structure that includes the first movableelectrode side fixed section 31 a and the second movable electrode sidefixed section 31 b that have the same potential as each other and themovable electrode side wiring 53 at a plurality of locations using thefirst contact section 54 a and the second contact section 54 b. For thisreason, it is possible to increase contact reliability.

In addition, since the respective number (number of the connecting partsto the substrate 4) of the connecting section 311 a and the connectingsection 311 b is two, it is possible to more stably connect thesubstrate 4 to the first movable electrode side fixed section 31 a andthe second movable electrode side fixed section 31 b. In addition, it ispossible to respectively dispose the third contact section 55 a or thefourth contact section 55 b between the two connecting sections 311 aand between the two connecting sections 311 b. That is, since it ispossible to dispose the third contact section 55 a and the fourthcontact section 55 b at the center, it is possible to more stablyelectrically connect the third contact section 55 a or the fourthcontact section 55 b and the first movable electrode side fixed section31 a or the second movable electrode side fixed section 31 b.

In addition, as described above, the conductive third contact section 55a is provided in contact with both the connecting section 311 a and themovable electrode side wiring 53 therebetween, and the conductive fourthcontact section 55 b is provided in contact with both the connectingsection 311 b and the movable electrode side wiring 53 therebetween.Thereby, it is possible to increase reliability of electrical contactbetween the movable electrode side structure 3 and the movable electrodeside wiring 53.

In addition, as described above, a plurality of projecting sections 43and the plurality of projecting sections 44 are provided overlappingwith the movable mass section 32 in planar view on the main surface ofthe substrate 4. Thereby, it is possible to regulate movement in anout-of-plane surface direction of the movable mass section 32 using theprojecting sections 43 and 44, and as a result, it is possible toprevent or reduce sticking of the movable mass section 32 on thesubstrate 4.

In addition, as described above, the first fixed electrode side fixedsection 21 a and the second fixed electrode side fixed section 21 brespectively have a portion which are positioned between the firstmovable electrode side fixed section 31 a and the second movableelectrode side fixed section 31 b in planar view. For this reason, it ispossible to shorten a distance between the two fixed electrode sidefixed sections, and as a result, it is possible to set further superiortemperature characteristics.

In addition, since the two first elastic sections 33 a extend from thefirst support section 312 a, and the two second elastic sections 33 bextend from the second support section 312 b, it is possible to increasea distance between the first elastic section 33 a and the second elasticsection 33 b. For this reason, it is possible to reduce the displacementin an out-of-plane surface direction (Z axis direction) of the movablemass section 32. For this reason, it is possible to improve impactresistance of the physical quantity sensor 1. In addition, in detectionof the physical quantity sensor 1, it is also possible to furtherseparate frequency of a vibration detection (for example, vibration dueto linear acceleration) mode according to a physical quantity that isdesired to be detected and a mode for unnecessary vibration in detection(so-called mode for vibration which is noise).

Second Embodiment

FIG. 7 is a planar view illustrating the physical quantity sensoraccording to the second embodiment of the invention.

The physical quantity sensor according to the embodiment, is the same asthe physical quantity sensor according to the first embodiment describedabove other than that the configuration of the respective first andsecond fixed electrode section and the movable electrode section isdifferent.

Here, the description below relates to the second embodiment, thedescription focuses on the differences from the embodiment describedabove, and similar matter is omitted from the description. In addition,in FIG. 7, the configuration which is the same as the first embodimentdescribed above is given the same reference numerals.

As shown in FIG. 7, a physical quantity sensor 1A of the embodiment hasa sensor element 10A and a substrate 4A which supports the sensorelement 10A. Here, the substrate 4A and the lid member (not shown in thedrawings) configures a package 20A which forms a space that houses thesensor element 10A.

The sensor element 10A has a first fixed electrode side fixed section 21c and a second fixed electrode side fixed section 21 d which aresupported on two projecting sections 42 c of the substrate 4A, and amovable electrode side structure 3A which is supported on fourprojecting sections 42 d of the substrate 4A.

The first fixed electrode side fixed section 21 c has a first fixedelectrode section 213 c which is connected to the first extendingsection 212 a. The first fixed electrode section 213 c extends along the+X axis direction from the first extending section 212 a and has aplurality of first fixed electrode fingers 2131 c which are disposedlined up at intervals with a gap along the Y axis direction, andconfigure the “first fixed electrode comb section” which has acomb-tooth shape.

In the same manner, the second fixed electrode side fixed section 21 dhas a second fixed electrode section 213 d which is connected to thesecond extending section 212 b. The second fixed electrode section 213 dextends along the −X axis direction from the second extending section212 b, has a plurality of second fixed electrode fingers 2131 d whichare disposed lined up at intervals with a gap along the Y axisdirection, and configure the “second fixed electrode comb section” whichhas a comb-tooth shape.

In the embodiment, the plurality of first fixed electrode fingers 2131 c(first fixed electrode comb section) which has the first fixed electrodesection 213 c and a plurality of second fixed electrode fingers 2131 d(second electrode comb section) which has a second fixed electrodesection 213 d are respectively divided in an electrode finger group madefrom a plurality of electrode fingers which are disposed at one side inthe Y axis direction and an electrode finger group made from a pluralityof electrode fingers which are disposed on another side, and a distancebetween the electrode finger group in each electrode comb section islarger than the gap between the electrode fingers in each electrodefinger group.

The movable electrode side structure 3A has a linking section 34 whichlinks the first movable electrode side fixed section 31 a and the secondmovable electrode side fixed section 31 b and a movable mass section 32Awhich is supported via the first elastic section 33 a and the secondelastic section 33 b with respect to the first movable electrode sidefixed section 31 a and the second movable electrode side fixed section31 b.

The linking section 34 extends along the Y axis direction so as to passbetween the connecting section 211 a of the first fixed electrode sidefixed section 21 c and the connecting section 211 b of the second fixedelectrode side fixed section 21 d in planar view, an end section on the+Y axis direction side of the linking section 34 is connected to thefirst movable electrode side fixed section 31 a and an end section onthe −Y axis direction side of the linking section 34 is connected to thesecond movable electrode side fixed section 31 b. Here, the firstmovable electrode side fixed section 31 a, the second movable electrodeside fixed section 31 b, and the linking section 34 are able to be saidto configure one “movable electrode side fixed section”.

In this manner, since the linking section 34 links the first movableelectrode side fixed section 31 a and the second movable electrode sidefixed section 31 b, and is configured by the same material as the firstmovable electrode side fixed section 31 a and the second movableelectrode side fixed section 31 b, it is possible to electricallyconnect the first movable electrode side fixed section 31 a and thesecond movable electrode side fixed section 31 b via the linking section34. For this reason, it is possible to reduce the occurrence of apotential difference between the first movable electrode side fixedsection 31 a and the second movable electrode side fixed section 31 b,and realize stable sensor characteristics. In addition, since thelinking section 34 fixes the first movable electrode side fixed section31 a and the second movable electrode side fixed section 31 b using thesame material, it is possible to collectively form the two movableelectrode side fixed sections from the same substrate.

In planar view, the movable mass section 32A has a shape which isenclosed by the first fixed electrode side fixed section 21 c, thesecond fixed electrode side fixed section 21 d, the first movableelectrode side fixed section 31 a, the second movable electrode sidefixed section 31 b, and the linking section 34.

The movable mass section 32A has a frame section 321A which is a frameshape in planar view, a first movable electrode section 322 c and asecond movable electrode section 322 d which are connected to the framesection 321A, and a first weight section 323 a and a second weightsection 323 b. Here, the first movable electrode section 322 c extendsalong the −X axis direction from the frame section 321A and has aplurality of first movable electrode fingers 3221 c which is disposedlined up at intervals with a gap along the Y axis direction so as tomesh with a gap at intervals with respect to a plurality of first fixedelectrode fingers 2131 c (first fixed electrode comb section) of thefirst fixed electrode section 213 c described above, and configure the“first movable electrode comb section” which has a comb-tooth shape. Inthe same manner, the second movable electrode section 322 d extendsalong the +X axis direction from the frame section 321A and has aplurality of second movable electrode fingers 3221 d which is disposedlined up at intervals with a gap along the Y axis direction so as tomesh with a gap at intervals with respect to a plurality of second fixedelectrode fingers 2131 d (second fixed electrode comb section) of thesecond fixed electrode section 213 d described above, and configure the“second movable electrode comb section” which has a comb-tooth shape.

In the embodiment, the plurality of electrode fingers (first movableelectrode comb section) which has the first movable electrode section322 c and a plurality of electrode fingers (second movable electrodecomb section) which has a second movable electrode section 322 d arerespectively divided in an electrode finger group made from a pluralityof electrode fingers which are disposed at one side in the Y axisdirection and an electrode finger group made from a plurality ofelectrode fingers which are disposed on another side, and a distancebetween the electrode finger group in each electrode comb section islarger than the gap between the electrode fingers in each electrodefinger group.

Then, the first weight section 323 a extends along the −X axis directionfrom the frame section 321A so as to enter between two electrode fingergroups (in more detail, between two electrode finger groups of the firstfixed electrode section 213 c described above) of the first movableelectrode section 322 c. In the same manner, the second weight section323 b extends along the +X axis direction from the frame section 321A soas to enter between two electrode finger groups (in more detail, twoelectrode finger groups of the second fixed electrode section 213 ddescribed above) of the second movable electrode section 322 d.

Here, the distance between the first weight section 323 a and oneelectrode finger group of the first movable electrode section 322 c isequal to a distance between the electrode fingers in the electrodefinger group. In the same manner, the distance between the second weightsection 323 b and one electrode finger group of the second movableelectrode section 322 d is equal to a distance between the electrodefingers in the electrode finger group. Thereby, it is possible for thefirst weight section 323 a and the second weight section 323 brespectively function as a portion of the first movable electrodesection 322 c and the second movable electrode section 322 d.

It is possible to realize superior temperature characteristics alsousing the physical quantity sensor 1A according to the second embodimentas described above.

2. Electronic Device

Subsequently, an electronic device in which the physical quantity sensor1 is used will be described in detail based on FIGS. 8 to 10.

FIG. 8 is a perspective view schematically illustrating a configurationof a mobile type personal computer which is an example of an electronicdevice in the invention.

In the drawing, a personal computer 1100 is configured by a main bodysection 1104 which includes a keyboard 1102, and a display unit 1106which is provided with a display section 1108, and the display unit 1106is supported so as to be able to rotate via a hinge structure sectionwith respect to the main body section 1104. The physical quantity sensor1 which functions as a gyro sensor is built in to such a personalcomputer 1100.

FIG. 9 is a perspective view schematically illustrating a configurationof a mobile phone which is an example of the electronic device in theinvention.

In the drawing, a mobile phone 1200 is provided with a plurality ofoperation buttons 1202, a receiving port 1204, and a transmission port1206, and a display section 1208 is disposed between the operationbuttons 1202 and the receiving port 1204. The physical quantity sensor 1which functions as the gyro sensor is built in to such a mobile phone1200.

FIG. 10 is a perspective view illustrating a configuration of a digitalstill camera which is an example of the electronic device of theinvention. Here, the drawing also illustrates the connection of anexternal device in a simplified manner. Here, a normal camera, withrespect to photosensitizing a silver halide photographic film using anoptical image of a subject, and a digital still camera 1300 generate animaging signal (image signal) by carrying out photoelectric conversionon an optical image of a subject using an imaging element such as acharge coupled device (CCD).

The display section 1310 is provided on the rear surface of a case(body) 1302 in the digital still camera 1300, and is configured toperform display based on the imaging signal using the CCD, and thedisplay section 1310 functions as a viewfinder which displays thesubject as an electronic image.

In addition, a light-receiving unit 1304 which includes an optical lens(imaging optical system), a CCD, and the like is provided at the frontsurface side (the rear surface side in the drawing) of the case 1302.

A subject image which is displayed on the display section 1310 isconfirmed by a photographer, and at the point in time when a shutterbutton 1306 is pressed down, the imaging signal of the CCD istransferred and stored in a memory 1308.

In addition, a video signal output terminal 1312 and an input and outputterminal 1314 for data communication are provided on a side surface ofthe case 1302 in the digital still camera 1300. Then, as illustrated, atelevision monitor 1430 is connected to the video signal output terminal1312, or a personal computer 1440 is connected to the input and outputterminal 1314 for data communication respectively according to need.Furthermore, using a predetermined operation, the imaging signal whichis stored in the memory 1308 is configured so as to be output to thetelevision monitor 1430 or the personal computer 1440.

The physical quantity sensor 1 which functions as the gyro sensor isbuilt in to such a digital still camera 1300.

Here, in addition to the personal computer in FIG. 8 (mobile-typepersonal computer), the mobile phone in FIG. 9, and the digital stillcamera in FIG. 10, it is also possible to apply the electronic devicewhich is provided with the physical quantity sensor of the invention to,for example, a smartphone, a tablet terminal, a timepiece, an inkjet-type discharging apparatus (for example, an ink jet printer), alaptop-type personal computer, a television, a video camera, a videotape recorder, a car navigation device, a pager, an electronic organizer(including those having a communication function), an electronicdictionary, an electronic calculator, an electronic game device, a wordprocessor, a work station, a video phone, a television monitor for crimeprevention, a pair of electronic binoculars, a POS terminal, medicalequipment (for example, an electronic thermometer, a blood pressuremeter, a blood glucose meter, an electrocardiographic measuring device,an ultrasonic diagnostic device, or an electronic endoscope), a fishfinder, various measurement equipment, an instrument (for example, aninstrument for a vehicle, an aircraft, or a ship), a flight simulator,and the like.

3. Mobile Body

Subsequently, a mobile body in which the physical quantity sensor 1 isused will be described in detail based on FIG. 11.

FIG. 11 is a perspective view illustrating a configuration of anautomobile which is an example of a mobile body of the invention.

The physical quantity sensor 1 which functions as the gyro sensor isbuilt in to an automobile 1500, and it is possible to detect the postureof a vehicle 1501 using the physical quantity sensor 1. The detectionsignal of the physical quantity sensor 1 is supplied to a vehicle bodyposture control device 1502, the vehicle body posture control device1502 detects the posture of the vehicle 1501 based on the detectionsignal, and according to the detection result, it is possible to controlthe hardness of suspension, or control brakes of individual wheels 1503.In addition, such posture control is able to be utilized in a bipedwalking robot and a radio controlled helicopter. As above, posturecontrol is realized in various mobile bodies, and the physical quantitysensor 1 is incorporated.

The physical quantity sensor, the electronic device, and the mobile bodyof the invention are described above based on the embodiments of thedrawings, but the invention is not limited thereto, and it is possiblefor the configuration of each section to be substituted with anarbitrary configuration which has the same function. In addition, otherarbitrary constructions may be added to the invention.

What is claimed is:
 1. A physical quantity sensor comprising: an X axis,a Y axis, and a Z axis that are orthogonal to each other; a substrate; afirst fixed electrode side fixed section that is fixed to the substrate,the first fixed electrode side fixed section having a first fixedelectrode section; a second fixed electrode side fixed section that isfixed to the substrate, and that is disposed to directly face the firstfixed electrode side fixed section in a direction along the X axis, thesecond fixed electrode side fixed section having a second fixedelectrode section, and the first and second fixed electrode sectionsbeing disposed side by side along the X axis; a first movable electrodeside fixed section and a second movable electrode side fixed sectionthat are disposed in a direction along the Y axis, and that are eachfixed to the substrate; a movable mass section that has a first movableelectrode section having a portion facing the first fixed electrodesection and a second movable electrode section having a portion facingthe second fixed electrode section; a first elastic section thatconnects the first movable electrode side fixed section and the movablemass section along the Y axis; and a second elastic section thatconnects the second movable electrode side fixed section and the movablemass section along the Y axis, wherein the first fixed electrode sidefixed section has a first connecting section that protrudes along theX-axis in a negative direction of the X-axis, the second fixed electrodeside fixed section has a second connecting section that protrudes alongthe X-axis in a positive direction of the X-axis, and the first andsecond fixed electrode side fixed sections are located between the firstmovable electrode side fixed section and the second movable electrodeside fixed section when viewed in a direction along the Z axis.
 2. Thephysical quantity sensor according to claim 1, wherein the first movableelectrode section has a plurality of first movable electrode fingersthat extend along the X axis, the second movable electrode section has aplurality of second movable electrode fingers that extend along the Xaxis, the first fixed electrode section has a plurality of first fixedelectrode fingers that extend along the X axis, and the second fixedelectrode section has a plurality of second fixed electrode fingers thatextend along the X axis.
 3. The physical quantity sensor according toclaim 2, wherein the first fixed electrode side fixed section has afirst extending section that extends along the Y axis and that supportsthe plurality of first fixed electrode fingers, the second fixedelectrode side fixed section has a second extending section that extendsalong the Y axis and that supports the plurality of second fixedelectrode fingers, and the first extending section is connected to thefirst connecting section, and the second extending section is connectedto the second connecting section.
 4. The physical quantity sensoraccording to claim 3, wherein the first extending section is disposed onone side in the direction along the X axis with respect to the firstmovable electrode side fixed section and the second movable electrodeside fixed section, and the second extending section is disposed on theother side in the direction along the X axis with respect to the firstmovable electrode side fixed section and the second movable electrodeside fixed section.
 5. The physical quantity sensor according to claim4, further comprising: a first fixed electrode side wiring provided onthe substrate and electrically connected to the plurality of first fixedelectrode fingers; and a second fixed electrode side wiring provided onthe substrate and electrically connected to the plurality of secondfixed electrode fingers, wherein the first extending section has aportion that is spaced apart from the substrate and that overlaps withthe first fixed electrode side wiring when viewed in the direction alongthe Z axis, and the second extending section has a portion that isspaced apart from the substrate and that overlaps with the second fixedelectrode side wiring when viewed in the direction along the Z axis. 6.The physical quantity sensor according to claim 5, further comprising: amovable electrode side wiring provided on the substrate and electricallyconnected respectively to the plurality of first movable electrodefingers and the plurality of second movable electrode fingers, whereintip end sections of each of the plurality of first movable electrodefingers and each of the plurality of second movable electrode fingersoverlap with the movable electrode side wiring when viewed in thedirection along the Z axis.
 7. The physical quantity sensor according toclaim 6, wherein at least one fixed section of the first movableelectrode side fixed section or the second movable electrode side fixedsection has a plurality of connecting sections that are connected to thesubstrate.
 8. The physical quantity sensor according to claim 7, furthercomprising: a conductive contact section contacting both of theconnecting section and the movable electrode side wiring, the conductivecontact section being positioned between the connecting section and themovable electrode side wiring.
 9. The physical quantity sensor accordingto claim 8, further comprising: a projecting section that is provided ona main surface of the substrate, the projecting section overlapping withthe movable mass section when viewed in the direction along the Z axis.10. The physical quantity sensor according to claim 9, furthercomprising: a linking section that links the first movable electrodeside fixed section and the second movable electrode side fixed section,the linking section being configured by the same material as the firstmovable electrode side fixed section and the second movable electrodeside fixed section.
 11. An electronic device comprising: the physicalquantity sensor according to claim
 1. 12. A movable body comprising: thephysical quantity sensor according to claim 1.